diff --git a/api.docurium b/api.docurium index 6aa5dcaf1..9e17817db 100644 --- a/api.docurium +++ b/api.docurium @@ -4,6 +4,8 @@ "input": "include/git2", "prefix": "git_", "output": "docs", + "branch": "gh-pages", + "examples": "examples", "legacy": { "input": {"src/git": ["v0.1.0"], "src/git2": ["v0.2.0", "v0.3.0"]} diff --git a/examples/libgit.c b/examples/libgit.c new file mode 100644 index 000000000..66df2687f --- /dev/null +++ b/examples/libgit.c @@ -0,0 +1,418 @@ +// [**libgit2**][lg] is a portable, pure C implementation of the Git core methods +// provided as a re-entrant linkable library with a solid API, allowing you +// to write native speed custom Git applications in any language which +// supports C bindings. +// +// [This file][ex] is an example of using that API in a real, compilable C file. +// Before published, this file is compiled and run to make sure it actually +// runs. As the API is updated, this file will be updated to demonstrate the +// new functionality. This project is [on GitHub][ex]. +// +// If you're trying to write something in C using [libgit2][lg], you will also want +// to check out the generated [API documentation][ap] and the [Usage Guide][ug]. We've +// tried to link to the relevant sections of the API docs in each section in this file. +// +// **libgit2** only implements the core plumbing functions, not really the higher +// level porcelain stuff. For a primer on Git Internals that you will need to know +// to work with Git at this level, check out [Chapter 9][pg] of the Pro Git book. +// +// [lg]: http://libgit2.github.com +// [ap]: http://libgit2.github.com/libgit2/modules.html +// [ug]: http://libgit2.github.com/api.html +// [pg]: http://progit.org/book/ch9-0.html +// [ex]: http://github.com/schacon/libgit2-examples + +// ### Includes + +// Including the `git2.h` header will include all the other libgit2 headers that you need. +// It should be the only thing you need to include in order to compile properly and get +// all the libgit2 API. +#include +#include + +int main (int argc, char** argv) +{ + // ### Opening the Repository + + // There are a couple of methods for opening a repository, this being the simplest. + // There are also [methods][me] for specifying the index file and work tree locations, here + // we are assuming they are in the normal places. + // + // [me]: http://libgit2.github.com/libgit2/group__git__repository.html + git_repository *repo; + git_repository_open(&repo, "/opt/libgit2-test/.git"); + + // ### SHA-1 Value Conversions + + // For our first example, we will convert a 40 character hex value to the 20 byte raw SHA1 value. + printf("*Hex to Raw*\n"); + char hex[] = "fd6e612585290339ea8bf39c692a7ff6a29cb7c3"; + + // The `git_oid` is the structure that keeps the SHA value. We will use this throughout the example + // for storing the value of the current SHA key we're working with. + git_oid oid; + git_oid_mkstr(&oid, hex); + + // Once we've converted the string into the oid value, we can get the raw value of the SHA. + printf("Raw 20 bytes: [%s]\n", (&oid)->id); + + // Next we will convert the 20 byte raw SHA1 value to a human readable 40 char hex value. + printf("\n*Raw to Hex*\n"); + char out[41]; + out[40] = '\0'; + + // If you have a oid, you can easily get the hex value of the SHA as well. + git_oid_fmt(out, &oid); + printf("SHA hex string: %s\n", out); + + // ### Working with the Object Database + // **libgit2** provides [direct access][odb] to the object database. + // The object database is where the actual objects are stored in Git. For + // working with raw objects, we'll need to get this structure from the + // repository. + // [odb]: http://libgit2.github.com/libgit2/group__git__odb.html + git_odb *odb; + odb = git_repository_database(repo); + + // #### Raw Object Reading + + printf("\n*Raw Object Read*\n"); + git_odb_object *obj; + git_otype otype; + const unsigned char *data; + const char *str_type; + int error; + + // We can read raw objects directly from the object database if we have the oid (SHA) + // of the object. This allows us to access objects without knowing thier type and inspect + // the raw bytes unparsed. + error = git_odb_read(&obj, odb, &oid); + + // A raw object only has three properties - the type (commit, blob, tree or tag), the size + // of the raw data and the raw, unparsed data itself. For a commit or tag, that raw data + // is human readable plain ASCII text. For a blob it is just file contents, so it could be + // text or binary data. For a tree it is a special binary format, so it's unlikely to be + // hugely helpful as a raw object. + data = (const unsigned char *)git_odb_object_data(obj); + otype = git_odb_object_type(obj); + + // We provide methods to convert from the object type which is an enum, to a string + // representation of that value (and vice-versa). + str_type = git_object_type2string(otype); + printf("object length and type: %d, %s\n", + (int)git_odb_object_size(obj), + str_type); + + // For proper memory management, close the object when you are done with it or it will leak + // memory. + git_odb_object_close(obj); + + // #### Raw Object Writing + + printf("\n*Raw Object Write*\n"); + + // You can also write raw object data to Git. This is pretty cool because it gives you + // direct access to the key/value properties of Git. Here we'll write a new blob object + // that just contains a simple string. Notice that we have to specify the object type as + // the `git_otype` enum. + git_odb_write(&oid, odb, "test data", sizeof("test data") - 1, GIT_OBJ_BLOB); + + // Now that we've written the object, we can check out what SHA1 was generated when the + // object was written to our database. + git_oid_fmt(out, &oid); + printf("Written Object: %s\n", out); + + // ### Object Parsing + // libgit2 has methods to parse every object type in Git so you don't have to work directly + // with the raw data. This is much faster and simpler than trying to deal with the raw data + // yourself. + + // #### Commit Parsing + // [Parsing commit objects][pco] is simple and gives you access to all the data in the commit + // - the // author (name, email, datetime), committer (same), tree, message, encoding and parent(s). + // [pco]: http://libgit2.github.com/libgit2/group__git__commit.html + + printf("\n*Commit Parsing*\n"); + + git_commit *commit; + git_oid_mkstr(&oid, "f0877d0b841d75172ec404fc9370173dfffc20d1"); + + error = git_commit_lookup(&commit, repo, &oid); + + const git_signature *author, *cmtter; + const char *message, *message_short; + time_t ctime; + unsigned int parents, p; + + // Each of the properties of the commit object are accessible via methods, including commonly + // needed variations, such as `git_commit_time` which returns the author time and `_message_short` + // which gives you just the first line of the commit message. + message = git_commit_message(commit); + message_short = git_commit_message_short(commit); + author = git_commit_author(commit); + cmtter = git_commit_committer(commit); + ctime = git_commit_time(commit); + + // The author and committer methods return [git_signature] structures, which give you name, email + // and `when`, which is a `git_time` structure, giving you a timestamp and timezone offset. + printf("Author: %s (%s)\n", author->name, author->email); + + // Commits can have zero or more parents. The first (root) commit will have no parents, most commits + // will have one, which is the commit it was based on, and merge commits will have two or more. + // Commits can technically have any number, though it's pretty rare to have more than two. + parents = git_commit_parentcount(commit); + for (p = 0;p < parents;p++) { + git_commit *parent; + git_commit_parent(&parent, commit, p); + git_oid_fmt(out, git_commit_id(parent)); + printf("Parent: %s\n", out); + git_commit_close(parent); + } + + // Don't forget to close the object to prevent memory leaks. You will have to do this for + // all the objects you open and parse. + git_commit_close(commit); + + // #### Writing Commits + // + // libgit2 provides a couple of methods to create commit objects easily as well. There are four + // different create signatures, we'll just show one of them here. You can read about the other + // ones in the [commit API docs][cd]. + // [cd]: http://libgit2.github.com/libgit2/group__git__commit.html + + printf("\n*Commit Writing*\n"); + git_oid tree_id, parent_id, commit_id; + + // Creating signatures for an authoring identity and time is pretty simple - you will need to have + // this to create a commit in order to specify who created it and when. Default values for the name + // and email should be found in the `user.name` and `user.email` configuration options. See the `config` + // section of this example file to see how to access config values. + author = git_signature_new("Scott Chacon", "schacon@gmail.com", + 123456789, 60); + cmtter = git_signature_new("Scott A Chacon", "scott@github.com", + 987654321, 90); + + // Commit objects need a tree to point to and optionally one or more parents. Here we're creating oid + // objects to create the commit with, but you can also use + git_oid_mkstr(&tree_id, "28873d96b4e8f4e33ea30f4c682fd325f7ba56ac"); + git_oid_mkstr(&parent_id, "f0877d0b841d75172ec404fc9370173dfffc20d1"); + + // Here we actually create the commit object with a single call with all the values we need to create + // the commit. The SHA key is written to the `commit_id` variable here. + git_commit_create_v( + &commit_id, /* out id */ + repo, + NULL, /* do not update the HEAD */ + author, + cmtter, + "example commit", + &tree_id, + 1, &parent_id); + + // Now we can take a look at the commit SHA we've generated. + git_oid_fmt(out, &commit_id); + printf("New Commit: %s\n", out); + + // #### Tag Parsing + // You can parse and create tags with the [tag management API][tm], which functions very similarly + // to the commit lookup, parsing and creation methods, since the objects themselves are very similar. + // [tm]: http://libgit2.github.com/libgit2/group__git__tag.html + printf("\n*Tag Parsing*\n"); + git_tag *tag; + const char *tmessage, *tname; + git_otype ttype; + + // We create an oid for the tag object if we know the SHA and look it up in the repository the same + // way that we would a commit (or any other) object. + git_oid_mkstr(&oid, "bc422d45275aca289c51d79830b45cecebff7c3a"); + + error = git_tag_lookup(&tag, repo, &oid); + + // Now that we have the tag object, we can extract the information it generally contains: the target + // (usually a commit object), the type of the target object (usually 'commit'), the name ('v1.0'), + // the tagger (a git_signature - name, email, timestamp), and the tag message. + git_tag_target((git_object **)&commit, tag); + tname = git_tag_name(tag); // "test" + ttype = git_tag_type(tag); // GIT_OBJ_COMMIT (otype enum) + tmessage = git_tag_message(tag); // "tag message\n" + printf("Tag Message: %s\n", tmessage); + + git_commit_close(commit); + + // #### Tree Parsing + // [Tree parsing][tp] is a bit different than the other objects, in that we have a subtype which is the + // tree entry. This is not an actual object type in Git, but a useful structure for parsing and + // traversing tree entries. + // + // [tp]: http://libgit2.github.com/libgit2/group__git__tree.html + printf("\n*Tree Parsing*\n"); + + git_tree *tree; + git_tree_entry *entry; + git_object *objt; + + // Create the oid and lookup the tree object just like the other objects. + git_oid_mkstr(&oid, "2a741c18ac5ff082a7caaec6e74db3075a1906b5"); + git_tree_lookup(&tree, repo, &oid); + + // Getting the count of entries in the tree so you can iterate over them if you want to. + int cnt = git_tree_entrycount(tree); // 3 + printf("tree entries: %d\n", cnt); + + entry = git_tree_entry_byindex(tree, 0); + printf("Entry name: %s\n", git_tree_entry_name(entry)); // "hello.c" + + // You can also access tree entries by name if you know the name of the entry you're looking for. + entry = git_tree_entry_byname(tree, "hello.c"); + git_tree_entry_name(entry); // "hello.c" + + // Once you have the entry object, you can access the content or subtree (or commit, in the case + // of submodules) that it points to. You can also get the mode if you want. + git_tree_entry_2object(&objt, repo, entry); // blob + + // Remember to close the looked-up object once you are done using it + git_object_close(objt); + + // #### Blob Parsing + // + // The last object type is the simplest and requires the least parsing help. Blobs are just file + // contents and can contain anything, there is no structure to it. The main advantage to using the + // [simple blob api][ba] is that when you're creating blobs you don't have to calculate the size + // of the content. There is also a helper for reading a file from disk and writing it to the db and + // getting the oid back so you don't have to do all those steps yourself. + // + // [ba]: http://libgit2.github.com/libgit2/group__git__blob.html + + printf("\n*Blob Parsing*\n"); + git_blob *blob; + + git_oid_mkstr(&oid, "af7574ea73f7b166f869ef1a39be126d9a186ae0"); + git_blob_lookup(&blob, repo, &oid); + + // You can access a buffer with the raw contents of the blob directly. + // Note that this buffer may not be contain ASCII data for certain blobs (e.g. binary files): + // do not consider the buffer a NULL-terminated string, and use the `git_blob_rawsize` attribute to + // find out its exact size in bytes + printf("Blob Size: %d\n", git_blob_rawsize(blob)); // 8 + git_blob_rawcontent(blob); // "content" + + // ### Revwalking + // + // The libgit2 [revision walking api][rw] provides methods to traverse the directed graph created + // by the parent pointers of the commit objects. Since all commits point back to the commit that + // came directly before them, you can walk this parentage as a graph and find all the commits that + // were ancestors of (reachable from) a given starting point. This can allow you to create `git log` + // type functionality. + // + // [rw]: http://libgit2.github.com/libgit2/group__git__revwalk.html + + printf("\n*Revwalking*\n"); + git_revwalk *walk; + git_commit *wcommit; + + git_oid_mkstr(&oid, "f0877d0b841d75172ec404fc9370173dfffc20d1"); + + // To use the revwalker, create a new walker, tell it how you want to sort the output and then push + // one or more starting points onto the walker. If you want to emulate the output of `git log` you + // would push the SHA of the commit that HEAD points to into the walker and then start traversing them. + // You can also 'hide' commits that you want to stop at or not see any of their ancestors. So if you + // want to emulate `git log branch1..branch2`, you would push the oid of `branch2` and hide the oid + // of `branch1`. + git_revwalk_new(&walk, repo); + git_revwalk_sorting(walk, GIT_SORT_TOPOLOGICAL | GIT_SORT_REVERSE); + git_revwalk_push(walk, &oid); + + const git_signature *cauth; + const char *cmsg; + + // Now that we have the starting point pushed onto the walker, we can start asking for ancestors. It + // will return them in the sorting order we asked for as commit oids. + // We can then lookup and parse the commited pointed at by the returned OID; + // note that this operation is specially fast since the raw contents of the commit object will + // be cached in memory + while ((git_revwalk_next(&oid, walk)) == GIT_SUCCESS) { + error = git_commit_lookup(&wcommit, repo, &oid); + cmsg = git_commit_message_short(wcommit); + cauth = git_commit_author(wcommit); + printf("%s (%s)\n", cmsg, cauth->email); + git_commit_close(wcommit); + } + + // Like the other objects, be sure to free the revwalker when you're done to prevent memory leaks. + // Also, make sure that the repository being walked it not deallocated while the walk is in + // progress, or it will result in undefined behavior + git_revwalk_free(walk); + + // ### Index File Manipulation + // + // The [index file API][gi] allows you to read, traverse, update and write the Git index file + // (sometimes thought of as the staging area). + // + // [gi]: http://libgit2.github.com/libgit2/group__git__index.html + + printf("\n*Index Walking*\n"); + + git_index *index; + unsigned int i, e, ecount; + + // You can either open the index from the standard location in an open repository, as we're doing + // here, or you can open and manipulate any index file with `git_index_open_bare()`. The index + // for the repository will be located and loaded from disk. + git_index_open_inrepo(&index, repo); + + // For each entry in the index, you can get a bunch of information including the SHA (oid), path + // and mode which map to the tree objects that are written out. It also has filesystem properties + // to help determine what to inspect for changes (ctime, mtime, dev, ino, uid, gid, file_size and flags) + // All these properties are exported publicly in the `git_index_entry` struct + ecount = git_index_entrycount(index); + for (i = 0; i < ecount; ++i) { + git_index_entry *e = git_index_get(index, i); + + printf("path: %s\n", e->path); + printf("mtime: %d\n", (int)e->mtime.seconds); + printf("fs: %d\n", (int)e->file_size); + } + + git_index_free(index); + + // ### References + // + // The [reference API][ref] allows you to list, resolve, create and update references such as + // branches, tags and remote references (everything in the .git/refs directory). + // + // [ref]: http://libgit2.github.com/libgit2/refs_8h.html + + printf("\n*Reference Listing*\n"); + + // Here we will implement something like `git for-each-ref` simply listing out all available + // references and the object SHA they resolve to. + git_strarray ref_list; + git_reference_listall(&ref_list, repo, GIT_REF_LISTALL); + + const char *refname, *reftarget; + git_reference *ref; + + // Now that we have the list of reference names, we can lookup each ref one at a time and + // resolve them to the SHA, then print both values out. + for (i = 0; i < ref_list.count; ++i) { + refname = ref_list.strings[i]; + git_reference_lookup(&ref, repo, refname); + + switch (git_reference_type(ref)) { + case GIT_REF_OID: + git_oid_fmt(out, git_reference_oid(ref)); + printf("%s [%s]\n", refname, out); + break; + + case GIT_REF_SYMBOLIC: + printf("%s => %s\n", refname, git_reference_target(ref)); + break; + } + } + + git_strarray_free(&ref_list); + + // Finally, when you're done with the repository, you can free it as well. + git_repository_free(repo); +} + diff --git a/examples/showindex.c b/examples/showindex.c new file mode 100644 index 000000000..908a114f4 --- /dev/null +++ b/examples/showindex.c @@ -0,0 +1,43 @@ +#include +#include + +int main (int argc, char** argv) +{ + git_repository *repo; + git_index *index; + unsigned int i, e, ecount; + git_index_entry **entries; + git_oid oid; + + char out[41]; + out[40] = '\0'; + + git_repository_open(&repo, "/tmp/gittalk/.git"); + + git_index_open_inrepo(&index, repo); + git_index_read(index); + + ecount = git_index_entrycount(index); + for (i = 0; i < ecount; ++i) { + git_index_entry *e = git_index_get(index, i); + + oid = e->oid; + git_oid_fmt(out, &oid); + + printf("File Path: %s\n", e->path); + printf(" Blob SHA: %s\n", out); + printf("File Size: %d\n", (int)e->file_size); + printf(" Device: %d\n", (int)e->dev); + printf(" Inode: %d\n", (int)e->ino); + printf(" UID: %d\n", (int)e->uid); + printf(" GID: %d\n", (int)e->gid); + printf(" ctime: %d\n", (int)e->ctime.seconds); + printf(" mtime: %d\n", (int)e->mtime.seconds); + printf("\n"); + } + + git_index_free(index); + + git_repository_free(repo); +} +